The structure-activity relationship (SAR) study was carried out by comparing testosterone production-promoting activities of all the new compounds along with nine related Epimedium flavonols, revealing that the new 8-prenylated quercetin glycosides (subtype 3′-hydroxyldemethylicaritin in Type B) exhibited lower testosterone production-promoting activities in rat primary Leydig cells than Epimedium flavonols of subtype demethylicaritin in Type A, but possessed higher activities than the Epimedium flavonols of subtype icaritin in Type A. Combining our discoveries and literature survey, a revised classification of Epimedium flavonols was proposed as Type A (8-prenylated kaempferol based), which was further subdivided into subtype icaritin and subtype demethylicaritin, and Type B (8-prenylated quercetin based), which was further subdivided into subtype 3′-hydroxylicaritin and subtype 3′-hydroxyldemethylicaritin. acuminatum for the first time, and their structures were characterized based on spectroscopic methods including 1D and 2D NMR, and HRESIMS.

Furthermore, guided by LC-MS profiling, three new 8-prenylated quercetin glycosides (3′-hydroxylikarisoside C, 3′-hydroxylepimedoside E, 3′-hydroxyldiphylloside B), one new anthocyanin (delphinidin-3- O- p-coumaroyl-sophoroside) and six known compounds were isolated from the flowers of E. by first conducting LC-MS analysis, leading to the identification of 32 compounds. Phytochemical investigation was carried out for the flowers of Epimedium acuminatum Franchet. 6Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China.

5State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

4Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.3Hubei Province Key Laboratory of Traditional Chinese Medicine Resource and Chemistry, Hubei University of Chinese Medicine, Wuhan, Hubei, China.2Key Laboratory of Biodiversity Science and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, China.1Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicines, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.Yixin Zhang 1, Cheng Zhang 2, Zihan Li 3, Cheng Zeng 4, Zhen Xue 4, Erwei Li 5, Gang Li 6, Juan Li 3, Guoan Shen 1, Chaoqun Xu 1, Yuanyue Wang 1, Baiping Ma 6, Hui Zhang 4* and Baolin Guo 1*

Investigating science and technology 8